This invention relates to computing devices. In particular, this invention relates portable computing devices, and to computer output display devices.
1. Baclground of the Invention
Personal computers have made huge strides in processor speed and static and dynamic memory costs in the last decade. Computer display technology however, while enjoying incremental improvements and a gradual decline in price, has not yet followed suit. Large high quality flat screen displays remain prohibitively expensive to manufacture because of residual manufacturing defect concentration and a simple mathematical relation which makes a mean number of expected defects per screen proportional to an area of that screen, meaning that a chance of manufacturing a defect-free display steadily declines with an area of that display. Large area CRT displays are less expensive, though still not having declined in cost in proportion to other computer resources, but are also bulky and occupy a volume which grows roughly as a cube of a linear display dimension. Large CRT displays are definitely not portable. Even high-end CRT displays leave something to be desired in ease of use and configuration, becoming essentially immovable appliances rather than an item of the physical desktop which can be arranged to suit the operator.
2. Summary of the Invention
In the description which follows, the term xe2x80x9ccomputing devicexe2x80x9d shall mean any device capable of performing computations or logical operations on an instruction set at least partially by electronic means, while the word xe2x80x9cportablexe2x80x9d means capable of being carried by a man, including but not limited to devices intended for routine movement from place to place, and also devices intended for semi-permanent installation on a desktop or work surface, which may be moved from time to time. The term xe2x80x9cinput panelxe2x80x9d is used herein to denote any generally flat device which enables a user to make inputs to a computing device, including but not limited to keyboards, keyboards equipped with xe2x80x9ctrack ballsxe2x80x9d, touch sensitive screens and numeric entry pads. The term xe2x80x9cportable computing devicesxe2x80x9d is used herein to designate generally laptop and xe2x80x9cpalm topxe2x80x9d personal computers, xe2x80x9cpersonal digital assistantsxe2x80x9d, and also special purpose portable electronics, including but not limited to surveying assistance devices and portable communications equipment at least partially embodying electronic logic or digital signal processing functions, including cellular telephones, and in particular cellular telephones with Internet access. The term xe2x80x9cdisplay panelxe2x80x9d denotes herein any generally flat device for the transient representation of data, including LED and electroluminescent display screens. The term xe2x80x9coutput panelxe2x80x9d as used in this disclosure is generally synonymous with a display panel, but may also include speakers or other output devices. Generically, both input panels and output panels found in a hinged or multiple leaved portable computing device are called xe2x80x9cfunctional panelsxe2x80x9d. A single functional panel may serve as both an input and output panel in some applications. When it is advantageous to emphasize this dual functionality, a panel may be referred to as a xe2x80x9cmulti-function panelxe2x80x9d. A multi-function panel may comprise two functions on a single face thereof, or show functionality on both an obverse and a reverse, that is, on both a front face and a rear face respectively. The xe2x80x9cfacexe2x80x9d of a display panel will be understood to be a side showing primarily a display function, if not otherwise specified.
In a context of computer display devices, a xe2x80x9cwindowxe2x80x9d shall have a customary meaning in this application, namely a defined area of output generated by a given program or process, with a peripheral appearance and standardized behavior controlled by an operating system common to a set of such windows.
Pursuant to the present invention, a portable computing device is equipped with multiple functional panels, at least two of which have a display function. The display panels are hinged, jointed or otherwise disposed to rotate or slide with respect to one another in a transition from a compact, transportable, configuration to an expanded use configuration. Several significant advantages accrue from using multiple movable display panels as opposed to a single rigid panel of equivalent display area.
First of all, flat display pricing is not linear in surface area. Manufacturing defects are more likely to result in rejected display devices the larger a surface area of the device. If a particular manufacturing technology results in 50% of all display panels of area A being discarded at the factory, then a simple scaling of the identical manufacturing technique to panels of area 2A is expected to result in rejection of 75% of the panels. Accordingly, all other cost factors being equal, productivity of the larger panels per pixel, that is, per display area, is half that of the smaller panels, and the cost of the larger panel is twice that of using two smaller displays.
Second, large displays may defeat the purpose of portability. Flat displays are rigid and a large single panel display places a lower limit on dimensions of the portable device. A multiple display device of equivalent total display area may be folded into a more nearly cubical shape with smaller maximum dimension than a single display device. A multiple display device with foldable or otherwise disposable display panels may also be adapted to a limited available space for use by a selective deployment of the display panels as needed or as possible.
Third, multiple display panels of a total effective surface area equivalent to that of a large single panel generally present information more effectively and attractively than a single display. A window of ⅓ the total area of a single display has linear dimensions 0.577 of those of the parent display. There is no way to tile three such windows of the same aspect ratio as a parent screen on the parent, and centering a single such window leaves a border of less than xc2xc of the original screen dimensions, which is difficult to effectively use for the display of information. Information on a single screen is also more difficult to visually differentiate than when presented on multiple adjacent displays and results more quickly in eye fatigue when repeatedly shifting attention between windows, as the eye may lack sufficient cues to enable an effortless shifting of attention.
Fourth, a single flat display panel necessarily involves a greater variation in angle of gaze relative to a surface normal of the panel compared to a multiple panel display, which may be angled inward towards the viewer or user in a xe2x80x9cwrap-aroundxe2x80x9d configuration.
Fifth, multiple displays allow an adaptation of display type to intended function, with a consequent cost reduction. A multiple display device may provide a single high-resolution color display panel for viewing of digital images and one or more less expensive monochromatic displays for data and word processing. Lower resolution may also be comfortably accepted in a display intended only to present legible alphanumeric characters rather than color or gray scale images. A text-only screen may also take advantage of simplified and hence faster video drivers. In general, an economic principle of division of labor is tapped by adapting device capabilities to function rather than providing a sufficient amount of a highest priced and most versatile resource to cover all required functions.
In summary, when presenting multiple blocks or windows of information multiple display screens or panels are often less expensive, more transportable, and more readable than a single display screen of equivalent area. A single display is preferred on the other hand when a large image is required to be displayed contiguously.
In a portable computing device according to the present invention, a multiplicity of flat display panels are movably joined to an input panel to form a collapsible multiple screen device. In a basic embodiment three screens take a form of a triptych for which the input panel forms a separate base panel.
The historical triptych is an artefact or ornament in which three image bearing panels are hinged or jointed along two common vertical edges thereof. In the traditional object the panels may be folded flat to protect and conceal image bearing interior surfaces, or opened to reveal these surfaces. The panels are generally left with a bend when opened rather than made completely coplanar, so that the artefact is self-supporting and the images are angled in towards a common point of view. In a multiple display panel portable computing device in a form of a triptych, three display panels or screens are similarly rotatably or foldably joined along two common vertical edges so as to be foldable into a single compact unit when not in use, with image display surfaces inwards. The display panels comprise a main or central panel and two auxiliary or wing panels. The central panel is in turn rotatably or foldably joined to an input panel along a common horizontal edge so that a complete portable computing device comprising an input panel and three display panels may be folded into a box-like object with input and display surfaces inwards, similar to a conventional laptop computer.
In a variation of the preceding embodiment, a fourth display panel is rotatably or foldably joined to the central display panel along a second horizontal edge, opposite of the common edge joining central panel and input panel, so that a total of four display panels are deployable in a hub and petal configuration. The fourth panel is angled upwards from the central panel of the triptych in use, to form a tetraptych, or four-paneled foldable form. Yet alternatively, the side panels may be eliminated from the just-mentioned four panel embodiment so that the input panel and two remaining display panels form a vertically oriented triptych, with the input panel, in a position of a wing, serving as base. This design may in turn be augmented by an addition of a further functional display or input panel connected to and foldable with the existing ones along an axis parallel to the remaining folding axes in a vertically oriented xe2x80x9cChinese screenxe2x80x9d or room-divider configuration. Display capacity of this device may be yet further augmented by an addition of wing screens or side panels to one or both substantially vertically oriented display panels, in analogy to the side panels in the first tripartite screen embodiment of the present invention A functional panel adjacent to the input panel, for stability serving as a element of a horizontal base in a deployed configuration, may be either an extension of the input panel, a display panel or a mixed-use panel. Any of the aforementioned multi-panel displays may also be used as stand-along units, without the input panel, as a peripheral to another computing device.
Another embodiment of the present invention also employs a basic triumvirate of display panels in accordance with the first described embodiment, but disposes the side or wing panels in a slidable rather than rotatable connection with the central display or output panel, so that the wing panels emerge from slots in the central panel. The wings or wing panels are conveniently half the width of the central panel in this embodiment, so that the wings may be contained in a single plane internal to the central panel in a retracted state. The wings are optionally rotatably mounted at a limit of sliding travel so that the wings may be angled inward after preliminary extension.
Use of half-width sliding wing panels results in smaller net screen area for given dimensions of a central display, but has an advantage that the side panels may be selectively deployed as needed in tight spaces. Full width sliding wing panels may also be employed, at a price of a thicker case element or central panel, or employment of more technically advanced thin displays.
A embodiment which folds into a very compact package is realized by further segmenting a single pair of input and central display panel along axes bisecting these now bi-folded panels parallel to their common edge. An overall folded package now shows four layers, and unfolds to form a product resembling a conventional laptop with a horizontally split screen. The split input panel, serving as a base for the unfolded device, may be replaced by half height horizontal input and display panels. In yet a further variation, sliding wings deploy from sides of each half of the vertically oriented split screen, to deploy a total of two or three larger and four smaller display panels, depending on a function of a second half of the horizontal base panel, input or output.
In terms of portable computing devices, the present invention finds particular application to Internet enabled cellular telephones. Using the Internet or a proprietary data source, cellular phones are moving beyond voice only communications to become mobile data relays for a user, supplying sports, weather, news, email and other information. Space is more at a premium in a cellular phone than in a laptop or even palm top computer, and such devices benefit greatly from compact extensible display technologies.
Flexible display screens may also be used as components of multiple display computing devices according to the present invention. A flexible video or display screen may be rolled up in a storage configuration and unrolled and stretched flat by a frame in a usage configuration. Lacking a requirement of rigidity, a flexible screen may be manufactured more thinly, and hence of reduced volume, relative to a rigid display panel. Flexible displays therefore reduce a volume requirement of a compactly folded unit. A flexible screen may in fact be the only way to obtain a given contiguous deployed display area on a small device, such as a cellular phone. Current cellular phone display panels are limited to a few lines of 40 character resolution or less. By combining at least one display in the megapixel range with a hand-held transceiver, cellular phones may fulfill their promise as wireless voice actuated portals to the Internet.